A biology professor claimed that theproportions of grades in his classes are the same. A sample of 100 studentsshowed the following frequencies: Grade A B C D E Frequency XXXXXXXXXX State the null...

A biology professor claimed that the proportions of grades in his classes are the same. A sample of 100 students showed the following frequencies:

GradeA B C D E

Frequency18 20 28 23 11

State the null and alternative hypotheses to be tested.

Determine the rejection region at the 5% significance level.

Compute the value of the test statistics.